Theoretical electronic structure of the molecules SrX (X = Li, Na, K) toward laser cooling study

The potential energy curves of the low-lying electronic states of the SrX (X = Li, Na, K) molecules have been investigated by using the ab initio CASSCF/(MRCI + Q) calculation. For the considered electronic states the spectroscopic constants T_e, ω_e, B_e, R_e, α_e, D_e the static and transition dipole moment curves, and the Franck-Condon factor (FCF) have been calculated. The study of the nuclear motion using the canonical functions approach allowed to determine different vibrational constants E_v, B_v, D_v and the turning points R_min and R_max up to the vibrational level v = 105. The comparison of the investigated data shows a very good agreement with those given in literature. These results have a great significance to experimentalists as they provide efficient routes to form cold alkali and alkaline earth molecules in low-lying vibrational states via experimental techniques.